Kamis, 23 Desember 2010

Oral Carcinosarcoma

Carcinosarcoma Definition

A malignant neoplasm that contains elements of carcinoma (cancer of epithelial tissue, which is skin and tissue that lines or covers the internal organs) and sarcoma (cancer of connective tissue, such as bone, cartilage, and fat) so extensively intermixed as to indicate neoplasia of epithelial and mesenchymal tissue.

Carcinomatous component is either blended or in transition with sarcomatous component.

Hypercellularity

Variable patterns of spindle-cell growth in sarcomatous component

Pleomorphism

Increased mitotic figures

Carcinomatous component is usually

Undifferentiated SCC

Squamous cell carcinoma

Poorly differentiated adenocarcinoma

It may also include

Adenoid cystic carcinoma

Epithelial myoepithelial carcinoma

Salivary duct carcinoma.

The sarcomatous component is usually,

Undifferentiated spindle cell sarcoma

Other reported sarcomatous elements include

Fibrosarcoma

Osteosarcoma

Leiomyosarcoma

Liposarcoma

Follicular dendritic cell sarcoma

Undifferentiated sarcoma

Myxoid sarcomas

Rhabdomyosarcoma

Chondrosarcoma

Areas of squamous differentiation are most consistently identified at the base of the polypoid lesion, at the advancing margins, or within invaginations at the surface where the epithelium is not ulcerated or denuded.(Condition is same in our patient)

CS will often present with little invasion into the underlying stroma, as it is polypoid.

Extensive infiltration and tissue destruction are common, as is perineural invasion and angioinvasion. Lymphatic spread is less common.

Metastases to other sites or lymph nodes may show the carcinomatous or the sarcomatous components alone, or they may be mixed.

So its extremely difficult in making the correct diagnosis of this tumor from a small biopsy specimen.

It is well illustrated by varies diagnoses based on biopsy specimens.

Immunohistochemistry

Immunohistochemical markers are used in aid of diagnosis.

Eg; -Cytokeratin

- Vimentin

- S-100

- Actin

Cytokeratins are proteins of keratin-containing intermediate filaments found in the intracytoplasmic cytoskeleton of epithelial tissue.there fore carcinomatous componentwhich is derived from epithelial tissue is strongly positive for cytokeratin

Vimentin is a member of the intermediate filament family of proteins that is especially found in connective tissue. This filament is used as a marker for mesodermally derived tissues, and as such can be used as an immunohistochemical marker for sarcomas.

Recent immunohistochemical and chromosomal analyses appear to have settled this argument in favour of the monoclonal hypothesis.

But some of the cases showed a sharp demarcation between the carcinomatous & sarcomatous elements without transition zone & different immunohistochemical staining pattern of the two components for epithelial & mesenchymal markers which suggests a different cell origin for each tumor cell types.

However possibility remains that the demarcation may not signify a different origin, since carcinoma components are demarcated in some sarcomatoid carcinomas in which the sarcomatous component derives frommetaplasia of the epithelial cells.

Treatment modalities for sarcomatoid carcinoma.

The primary treatment modality for sarcomatoid carcinoma should be the same as for squamous cell carcinoma which consists of;

SURGICAL EXCISION of the lesion with an adequate margin.

ADJUVANT IRRADIATION may be beneficial in patients who have positive surgical margin or who have nodal metastasis.

The role of the chemotherapy has not been established, but it maydecrease the incidence of recurrence or metastasis of primarily sarcomatous tissue.

Prognosis

Mean survival time of those dead of the disease is

2 years.

No clinical or histomorphological characteristic other than distant metastasis was found to be a reliable prognostic indicator.